Problem: The sum of $4$ consecutive odd numbers is $40$. What is the second number in this sequence?
Call the first number in the sequence $x$. The next odd number in the sequence is $x + 2$ The sum of the $4$ consecutive odd numbers is: $x+ (x + 2)+ (x + 4)+ (x + 6) = 40$ $4x + 12= 40$ $4x = 28$ $x = 7$ Since $x$ is the first number, $x + 2$ is the second odd number. Thus, the second number in the sequence is $9$.